The first is simple — add a capability similar to that of Air and Earth. This is probably not so much a change as just something it should be able to do, in comparison with the other gifts.

The character may see through water as if it were air, and able to enhance their vision to see over great distance. It also allows them awareness of anything that is touching the body of water — for this to function, the water must be reasonably contiguous and whole — a lake or a river — unless the character is also an elementalist.

The latter would allow viewing through fog or steam, for example.

The second is somewhat problematic, as it would be a change. The current method of scrying/communing requires a reflective surface that is currently reflecting the image of the subject — plus that image has to be reasonably clear and whole. Practically speaking, that has to be a mirror—people are rarely in a position to see themselves over a pool of water. Mirrors give the wrong "feel" to me, as there is an entire class of magic surrounding it. Also, think about how ovten you can reasonable think of seeing yourself in a mirror during a day — the caster might have to attempt this for hours on end. And on the other side, if the person is in a reflection, there's no IC way to refuse. Now we can get around those by simply using RP convenience. The caster just happened to try when the person just happened to be in front of a mirror, and not when it might be inconvenient for them. Of course this can have some amusing consequences at times, but that seems to be outweighed as you come to realize just how unlikely it happens to be. And consider if you are travelling — would anyone but a Pathi set up a mirror during rest stops just in case? Remember, it is not enough to have a mirror near — the person must be able to see their image, because that is what the caster would see.

So, I would propose that it makes more sense to bring this ability to its roots—namely, water. When the caster speaks the name of the person over their scrying pool, that call emanates from the closest water object in plain sight to the person called. This is audible, and the volume somewhat proportional to the size of that object. They answer that call by speaking the name of the caster. Only then does the image form in that water, and the conversation started.

This doesn't change the ability power-wise, but I think it fits better into RP. I suppose for continuity we don't need to get rid of the mirror definition, if that is a big problem. But we would commonly rely on the water linkage instead. So, instead of us having mirrors all over the place in our homes and buildings, we would have scrying pools. As we travel, perhaps many of us wear an earring from which hangs a small globe of water. And so on. It also provides an IC way for the person called to refuse — just don't say the caster's name.

However, I just realized that this does change one thing: You can no longer rely on starting a conversation with someone who OOCly agrees, but ICly would not. Perhaps we could define a method to do this, something that fits more in with the concept of "scrying" rather than just "communicating".

I support the idea of water over reflective surfaces.
As far as scrying vs communing; it's easy enough to cook up a rationale that a commune link is tenuous until the other party gives it their attention, and that the scrying link is a bit flakey at times because of that.

I haven't tried to commune with arcanis un+wa yet, so I don't know what the current message strings are, but one of my alts can attest that a well-configured commune gift can concisely describe the limitations of the gift through the message strings.

It looks like the configurable points for commune messaging are:
attempt To initiator, on attempt.
xattempt To receiver, on attempt.
fail To initiator, on failure.
succ To initiator, on success.
xsucc To receiver, on success.
finish To participants, on commune end.
prefix Prefix you see when you talk.
xprefix Prefix they see when you talk.
rprefix Prefix they see when they talk.
rxprefix Prefix you see when they talk.
(from +help commune admin)

So I would suggest expanding the scope of the proposed change to include any necessary adjustments to the messaging strings.